TV-Series
Description
Hydra Belle, known in Japanese as Haidora Beru, is a prominent character introduced early in the story as a self-proclaimed bounty hunter and a master of the mystical arts. Her full background is tied to a lineage of significant power; she is the daughter of Heads Hydra, a being capable of transforming into a massive three-headed dragon, and Nyen. This heritage is the source of her natural talent for spatial magic, a skill she has honed since childhood with encouragement from her father. As a member of the Hydra family, she has a younger brother named Knell, and she eventually discovers a profound familial connection to another main character, Fuyumi Yanagi, revealing them to be half-sisters through their shared mother. To her peers, she is often affectionately called by her nickname Bell, though her tendency to carry an oversized backpack has led Staz and Wolf to teasingly refer to her as Marshmallow or Daifuku.

At her core, Hydra Belle is a complex blend of bubbly charm and sharp cunning. Her personality is naturally energetic and girly, with a visible fondness for the color pink and cute stuffed animals, yet this cheerful demeanor belies a highly deceptive and clever intellect. She possesses an insatiable curiosity, particularly for anything that has been hidden or lost, a trait that serves her well in her treasure-hunting pursuits. Rather than being an objective-driven hero, her motivations are often personal and emotionally driven. A significant motivation is her growing attraction to powerful individuals, which manifests as a deep and enduring romantic interest in the vampire Staz. This infatuation influences many of her actions, from testing his strength to eventually confessing her feelings for him later in the manga. She also demonstrates a strong sense of loyalty and protectiveness toward those she cares about, specifically Fuyumi, once their familial bond is revealed.

Belle plays a multifaceted role in the story, acting as both a catalyst for conflict and a crucial ally. She is responsible for introducing the central plot device of the Human Resurrection Book, using it to instigate a fight between Staz and Wolf to gauge their abilities. Despite her mischievous and sometimes antagonistic methods, she ultimately becomes an indispensable member of the main group. Her unparalleled spatial magic provides the primary means of rapid transportation between the human world and the demon world, including access to her own isolated subspace known as the Grid Room, which she can use for imprisonment or combat. Her role expands from a curious observer to a key participant in the fight to resurrect Fuyumi and unravel the dark plots within the demon world.

Her key relationships define her character arc. Her dynamic with Staz is central, evolving from suspicion and testing to genuine affection and partnership. Their interactions are characterized by a playful, flirty bickering that reveals a natural chemistry. She is often attempting to impress him or assert dominance, while Staz remains mostly oblivious to her true feelings. In stark contrast, her relationship with Fuyumi begins with rivalry but transforms into a profound sisterly bond after learning they are related, leading Belle to betray her own family to help her escape. She also forms an unexpected and amiable connection with the werewolf Wolf, accompanying him on a journey to find his mother and even being mistaken for his girlfriend.

Throughout the narrative, Hydra Belle undergoes notable development. She starts as a somewhat selfish and mysterious treasure hunter who uses people as pawns for her entertainment. However, her experiences and emotional attachments lead her to genuine acts of sacrifice and loyalty, such as disobeying her mother by helping Fuyumi escape and later running away from home to protect her newfound bonds. Her skills as a combatant are directly tied to her lineage and magical prowess. As a most advanced spatial magician, her notable abilities are vast. She can transport herself and others anywhere by creating portals from any frame, such as a doorway or a window. She commands the Black Curtain, a specific gateway designed to connect the human and demon worlds. For offensive and defensive purposes, she can manifest energy squares that act as portals, redirecting attacks or even closing a portal around an opponent to spatially slice them into pieces. Furthermore, she can create the Grid Room, an isolated dimension that is completely inaccessible to anyone but herself, serving as an inescapable trap.